added option to select template engine (handlebars, mustache)

modules/swagger-codegen-cli/src/main/java/io/swagger/codegen/cmd/Generate.java

@@ -31,6 +31,8 @@ public class Generate implements Runnable {
     private String output = "";
     private String spec;
     private String templateDir;
+    private String templateEngine;
+    private String templateFileExtension;
     private String auth;
     private List<String> systemProperties = new ArrayList<>();
     private String configFile;
@@ -77,6 +79,14 @@ public class Generate implements Runnable {
         this.templateDir = templateDir;
     }
 
+    public void setTemplateEngine(String templateEngine) {
+        this.templateEngine = templateEngine;
+    }
+
+    public void setTemplateFileExtension(String templateFileExtension) {
+        this.templateFileExtension = templateFileExtension;
+    }
+
     public void setAuth(String auth) {
         this.auth = auth;
     }
@@ -218,6 +228,14 @@ public class Generate implements Runnable {
             configurator.setTemplateDir(templateDir);
         }
 
+        if (isNotEmpty(templateEngine)) {
+            configurator.setTemplateEngine(templateEngine);
+        }
+
+        if (isNotEmpty(templateFileExtension)) {
+            configurator.setTemplateFileExtension(templateFileExtension);
+        }
+
         if (isNotEmpty(apiPackage)) {
             configurator.setApiPackage(apiPackage);
         }

modules/swagger-codegen-cli/src/main/resources/oas3.yaml

@@ -173,6 +173,19 @@ components:
           title: "remove prefix of the operationId"
           description: "Remove prefix of operationId, e.g. config_getId => getId"
           x-option: "--remove-operation-id-prefix"
+        templateEngine:
+          type: "string"
+          title: "template engine"
+          description: "template engine to generate files. (default is 'mustache'"
+          example: "mustache, handlebars"
+          x-option: "--template-engine"
+          x-short-version: "-e"
+        templateFileExtension:
+          type: "string"
+          title: "template file extension"
+          description: "extension related to template files."
+          example: ".mustache, .hbs"
+          x-option: "--template-file-extension"
     ConfigHelp:
       x-command: "config-help"
       x-command-description: "Config help for chosen lang"